As LSI circuits are increasing in density, circuit line widths of semiconductor devices are becoming finer. Examples of methods of producing an exposure mask (also called a reticle, which is used in a stepper or a scanner) to be used to form a circuit pattern for such a semiconductor device include an electron beam writing technique with high resolution.
A writing apparatus using multiple beams enables irradiation with many beams at once (in a single shot) as compared with writing with a single electron beam, and thus markedly increases throughput. In such a multi-beam writing apparatus, for example, an electron beam emitted downwardly from an electron gun passes through an aperture member having a plurality of holes, thus forming multiple beams.
In these multi-beam writing apparatuses, for example, an attachment positional deviation of an aperture member or a dimensional deviation of holes arranged in the aperture member may cause a shot size to vary from writing adjustment to writing adjustment or from apparatus to apparatus. If writing is performed out of consideration of a variation in shot size, the whole of a layout design will be enlarged or reduced and the accuracy with which patterns are connected will be reduced, leading to a reduction in writing accuracy.